18 



for asthma. Travels, 1 . 35. Their seeds universally abound in a fixed oil, which 

 is expressed from some species, as the Rape, for various economical purposes. 



Linnceus divided this order, which is the same as his Tetradynamia, by 

 the form of the fruit, under two heads, bearing the names of Siliquosa and 

 Siliculosa. More recently, divisions have been founded upon the nature of 

 the plicature of the cotyledons, and the position of the radicle with respect 

 to them. It is difficult to say what degree of importance really deserves to 

 be attached to these characters, which are however in general use, and which 

 will probably continue to be employed for the purpose of distinction. 



The following are the modifications used by Decandolle : — 



1. The cotyledons are flat, with the radicle lying upon their edges. 

 (^PleurorhizecE.) 



Examples. Cheiranthus, Arabis, Alyssum. 



2. The cotyledons are flat, with the radicle lying upon their back.- 

 (Notorhize<^.) 



Examples. Sisymbrium, Erysimum, Lepidium. 



3. The cotyledons are folded lengthwise. {Orthoplocece.) 

 Examples. Brassica, Sinapis, Vella. 



4. The cotyledons are coiled up spirally. {Spiroloheoe.) 

 Examples. Bunias, Erucaria. 



5. The cotyledons, instead of being coiled up spirally, or folded length- 

 wise, are bent double. (Diplecolobece.) 



Examples. Heliophila, Subularia, 



X. FUMARIACE^. The Fumitory Tribe. 



FiiMARiACE/TL, Dec. Syst. 2. 105. (1821) ; Prodr. 1. 125. (1824) ; Lindl. Synops. 18. (1829.) 



Diagnosis. Polypetalous dicotyledons, with a* definite number of 

 hypogynous diadelphous stamens, concrete carpella, a 1 -celled ovarium, nar- 

 row parietal placentse, 2 sepals, and an irregular corolla. 



Anomalies. / 



Essential Characteb. — Sepals 2, deciduoiis. Petals 4, cniciate, parallel ; the 2 

 outer, either one or both, saccate at the base ; the 2 inner callous and coloured at the 

 apex, where they coliere and enclose the anthers and stigma. Stamens (J, in two parcels, 

 opposite the outer petals, very seldom all separate ; anthers membranous, the onter of each 

 parcel 1-celled, the middle one 2-celled. Ovarium snperior, l-celled ; ovula horizontal; 

 style fihform ; stigma with two or more points. Fruit various ; either an indehiscent 1- or 

 2-seeded nut, or a 2-valv'ed polyspermous pod. Seeds horizontal, shining, with an arillus. 

 yi/iMBien fleshy. Embryo minute, out of the axis ; In the indehiscent fruit straight; in 



those which dehisce somewliat arcuate Jlerhaceous plants, with brittle stems and a watery 



juice. Leaves usually alternate, multifid, often with tendrils. Flowers purple, wliite, or 

 yellowr. 



Affinities. The following are M. Decandolle's remarks upon this sub- 

 ject {Syst. 2. 106.): — " Fumariaceac are very near Papaveraceoe, on account 

 of their 2-leaved deciduous calyx, of the structure of the fruit of such species 

 as dehisce, and of their fleshy albumen ; but they differ, firstly, in their juice 

 being watery, instead of milky ; secondly, in their petals being usually irregular 

 and in cohesion with each other ; thirdly, in their diadelphous stamens, which 

 bear indifferently 1- and 2-celled anthers." The same learned writer also 

 points out the affinity that exists between them and CrucifcrBe, which differ 

 chiefly in the arrangement of their stamens, in the number of the leaves of the 

 calyx, in their regular petals and cxalbnminous seeds. I am, however, inclined 

 to suspect, that the floral envelopes of Fumariaceae are not rightly described. 



